Polishing cloth

ABSTRACT

A polishing cloth is adhered to a polishing belt including a window opening for end-point detection. A transparent film, including a liner, that transmits end-point detection light is adhered to a portion of the polishing cloth corresponding to the window opening of the polishing belt. Another liner is adhered via an adhesion layer to the adhesion surface of the polishing cloth at area other than the portion corresponding to the window opening. The polishing cloth includes the transparent film that transmits the end-point detection light at the portion corresponding to the window opening of the polishing belt so that an end point of the surface of the object to be polished can be detected through the transparent film. This prevents slurry to leak inside the belt compared to the conventional technology.

FIELD OF THE INVENTION

[0001] This invention relates to a polishing cloth (polishing pad) that is used, for example, when semiconductors are manufactured.

DESCRIPTION OF THE PRIOR ART

[0002] There has been a polishing cloth that is used, for example, when semiconductors are manufactured.

[0003] As shown in FIG. 3, plural pieces of polishing cloth 1 are adhered to a surface of a polishing belt 2 that is driven to rotate. An object to be polished 3 that is made to spin on the belt is polished with slurry (not shown in the drawings).

[0004] Window openings 5 for laser end-point detection are drilled at a fixed distance so that an end-point detection device 4 detects an end point of a surface state of the object to be polished 3.

[0005] However, there has been a problem that inferior detection occurs when the slurry leaks inside the polishing belt 2 from the window opening 5. There has been another problem that the slurry leaking inside makes the end-point detection device 4 and the like dirty.

SUMMERY OF THE INVENTION

[0006] It is hence an object of the present invention to provide a polishing cloth that prevents slurry to leak inside a belt compared to conventional technology.

[0007] To solve the foregoing drawbacks, this invention takes some technical steps, which are described next.

[0008] A polishing cloth according to the present invention is adhered to a polishing belt including a window opening for end-point detection. A transparent film that transmits end-point detection light is adhered to a portion of the polishing cloth corresponding to the window opening of the polishing belt, and a liner is adhered to the transparent film. Another liner is adhered via an adhesion layer to an adhesion surface of the polishing cloth facing the polishing belt at area other than the portion corresponding to the window opening.

[0009] The polishing cloth includes the transparent film that transmits the end-point detection light so that an end point of a surface state of an object to be polished can be detected through the transparent film.

[0010] The liner is adhered to the transparent film and the other liner is adhered via the adhesion layer to the adhesion surface facing the polishing belt at area other than the portion of the polishing cloth corresponding to the window opening. Therefore, when the polishing cloth is adhered to the polishing belt, both the liner of the transparency film corresponding to the window opening and the other liner of the area other than the portion of the polishing cloth corresponding to the window opening are peeled off so that the polishing cloth adhered to the polishing belt is unlikely to come off from the belt at the time of polishing.

[0011] The above and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a plane view showing a state of polishing cloths adhered to a polishing belt according to an embodiment of the present invention.

[0013]FIG. 2 is an enlarged perspective view, partly in sections, of a main part of the polishing cloth according to FIG. 1.

[0014]FIG. 3 is a perspective view showing a situation how the polishing cloths are used.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] As showing FIG. 1 through FIG. 3, plural pieces of polishing cloth 1 are adhered to a surface of a polishing belt 2 that is driven to rotate. An object to be polished 3 that is made to spin on the polishing belt 2 is polished with slurry (not shown in the drawings). Window openings 5 for laser end-point detection are drilled at a fixed distance so that an end-point detection device 4 detects an end point of a surface state of the object to be polished 3.

[0016] As shown FIG. 2, the polishing cloth 1 based on a base pad 6 is used after being adhered to the polishing belt 2 including the window opening 5 for end-point detection.

[0017] A transparent film 7 that transmits end-point detection laser light is disposed at a portion of the polishing cloth 1 corresponding to the window opening 5 of the polishing belt 2. In this embodiment, a round PET film is used as the transparent film 7. The PET film is made of a raw material, named “Super Clean” produced by TORAY Industries, Inc., that makes laser light detection possible. A liner 9 (an exfoliation sheet) is adhered to the outside of the transparent film 7 (the round PET film). A liner 9′ (an exfoliation sheet) is adhered via an adhesion layer of double-sided tape 10 to an adhesion surface of the polishing cloth 1 facing the polishing belt 2 at area other than the portion corresponding to the window opening 5.

[0018] The polishing cloth 1, for example, is formed by the way described next.

[0019] First of all, the double-sided tape 10 is adhered to an adhesion surface of the base pad 6 with the polishing cloth 1 facing the polishing belt 2. A portion of the liner, corresponding to the window opening 5 of the polishing belt 2, out of the liner 9′ of the adhered double-sided tape 10 is circularly cut out. The above mentioned round PET film 7 is put over the cut portion of the polishing cloth 1 and is adhered thereto.

[0020] Next, the state how the polishing cloth 1 is used according to this embodiment is described.

[0021] The transparent film 7 that transmits the end-point detection light is adhered to the portion of the polishing cloth 1 corresponding to the window opening 5 of the polishing belt 2. The end point of the surface state of the object to be polished 3 can be detected through the transparent film 7.

[0022] Moreover, the liner 9 is adhered to the transparent film 7 for laser light and the liner 9′ is adhered via the adhesion layer of the double-sided tape 10 to the adhesion surface the polishing cloth 1 facing the polishing belt 2 at area other than the portion corresponding to the window opening 5. Therefore, when the polishing cloth 1 is adhered to the polishing belt 2, both the liner 9 of the portion corresponding to the window opening 5 and the liner 9′ of the area other than the portion corresponding to the window opening 5 are peeled off so that the polishing cloth 1 adhered to the polishing belt 2 is unlikely to come off from the belt at the time of turning a corner of the belt when polishing.

[0023] The present invention has the above mentioned structure and the polishing cloth is adhered to the polishing belt so that it may not come off from the belt. Therefore, the present invention can provide the polishing cloth that prevents slurry to leak inside the belt. 

What is claimed is:
 1. A polishing cloth to be adhered to a polishing belt including a window opening for end-point detection comprising: a transparent film, including a liner, that transmits end-point detection light adhered to a portion of the polishing cloth corresponding to the window opening of the polishing belt; a liner, adhered to an adhesion surface of the polishing cloth facing the polishing belt at area other than the portion corresponding to the window opening; and an adhesion layer.
 2. A polishing cloth to be adhered to a polishing belt including a window opening for end-point detection comprising: a transparent film, including an exfoliation sheet on an outside thereof, that transmits end-point detection light disposed at a portion of the polishing cloth corresponding to the window opening of the polishing belt; an exfoliation sheet, adhered to an adhesion surface of the polishing cloth facing the polishing belt at area other than the portion corresponding to the window opening; and an adhesion layer.
 3. A polishing cloth to be adhered to a polishing belt including a window opening for end-point detection comprising: a base pad; and a transparent film that transmits end-point detection light, double-sided tape adhered to an adhesion surface of the base pad facing the polishing belt, a portion of an exfoliation sheet, corresponding to the window opening of the polishing belt, out of the exfoliation sheet of the adhered double-sided tape being cut out and the transparent film that transmits end-point detection light being put over a cut portion of the polishing cloth and adhered thereto. 